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Symbol Library
Graphical representation

Looking for graphic symbols to be used on SCADA WEB HMI application. Especially looking for Digital LED indicator for Process Value and Set Value, Pumps, HVAC Symbols etc.

Please direct me to the websites for getting free/buying such graphical symbols.

Try the Symbol Factory (no not free and neither should it be):

The answer to that is going to depend on how your web based HMI will work. I've designed one that you can create whatever you want as part of the web page and manipulate it (rotate, change colour, etc.). It comes with a set of common symbols, but you can make your own easily enough and manipulate them using one of the standard methods.

Most "web based" HMIs however are actually a collection of Java (or ActiveX) applets. That means that each "symbol" is actually an independent program that happens to run inside the web browser. In that case, you have to live with whatever they happen to give you, and they typically all have to be designed to work together so you can't just mix and match them.

In either case, a web based HMI needs some sort of server. It needs a web server to serve up the web page (and other files, including the Java/ActiveX applets). It also needs a communications server to act a a middleman between your web browser and the PLC/SCADA/whatever. Both functions typically need to be built into the same piece of software (because of the way that newer web browsers work).

So, what are you looking for? Do you have an existing web based HMI and are just looking to expand the Java (ActiveX) applet collection? Does it need to work with a specific HMI/SCADA system? What sort of equipment does it need to be able to talk with, and using what protocol? Or do you have nothing at present and are looking around to see what is available?

As a follow-up to my own post, if you are just looking for a clip-art library with control style artwork, you can ignore my previous post. It was based on the assumption that you are looking for something to actually make a web based HMI.

If you already have a web based HMI and just want more clip-art, then you should be specific about what software you want to use it with. Also, do you want to animate the clip-art, or do you just want them for background images?

The item that Francis pointed out in his post is a clip-art library, which is a collection of static images. I was previously talking about the software to drive the system. So, those two posts were talking about two completely different things. If you want any more suggestions, you will need to be more specific about what you are trying to do.

Mike Griffin, Francis and Bob,

I appreciate your inputs to my thread. I am a beginner and am trying to set my first project on a WEB HMI software. I have to indicate Process Value and Set Value Temperatures on the screen but in the form of red LED 7 segment display for PV and yellow LED 7 segment display for SV. I also want to display and animate refrigeration units (or likes) to represent the actual operation. These ActiveX symbols are not available with the software package. I shall be using Modbus TCP as my courier service. I wish to make my web page as attractive as possible. Are these graphic symbols available? and where can I find them?

The link which Francis gave to "Softwaretoolbox" is to their clip art library. I believe they also have MS ActiveX versions. You can ask their sales department about whether they have the symbols you are looking for.

If you are using an off the shelf web based HMI (you have avoided saying if that is the case), then your best bet is to contact whomever you bought it from and ask them about additional libraries that are compatible with it. You will have to pay for them though.

You may also wish to have a look at my free/open source project:

There are three packages there, the one you would want is MBTools. The web site for the project is:

There are download instructions at:

You can read that for detailed instructions on downloading the correct package.

The MBTools package contains several programs, one of which is HMIServer. HMIServer has a data server which serves your web pages, communicates with the web browser, and contains a Modbus/TCP driver for communicating with a field device (e.g. PLC).

Here are some screen shots:

I don't have 7 segment LED symbols at the moment though. You can create your own graphics however and use that in the HMI instead of the samples that I provided.

Not completely true. DAQConnect ( provides the web server for you so you don't have to expose your systems to the internet and runs in Javascript, so its all native (no applets). The communications link between DAQConnect and PLC/SCADA can actually be embedded in the PLC itself, or linked to existing SCADA using a DLL or simple script, so no separate "communication server" is really needed.

But back to the original question. Symbol Factory is an excellent choice and has symbols ready to go. If you have more time than money, you might also want to look at downloading Google Sketchup (free). There are a lot of industrial objects in their 3D warehouse that you can edit in Sketchup and export as a 2D clipart. The licensing on the 3D library allows the use of most any of the objects in other applications.

In reply to Matt Warshawsky: I'm not sure who you are disagreeing with. If it was me, all you are saying is that with DAQConnect some of the system components are provided remotely by the DAQConnect company as an external hosted application. The components are still the same in either case.

DAQConnect is targeted at a completely different set of applications than most other web based HMI systems. With DAQConnect you send the DAQConnect company the data and they actually serve the resulting web pages to the general public outside your facility. The data flow is one way only.

Most other web based HMI systems (including my own HMIServer) are intended for internal networks, just like traditional HMI systems. That means you need to provide all the system components yourself (that can all be built into a single program though). The data flows in both directions (i.e. you can send commands back to the equipment as well as receive data). You shouldn't expose these types of systems to the public because they would allow other people to control your equipment. You could use them remotely, but you have to provide a secure communications channel by other means (e.g. ssh tunnelling).

"Web based HMI" can mean different things, and not all options are suitable for every application.

Re: Sorry, I was not disagreeing with your last post, but rather your first one and the part about needing a communications server (and it being a part of the HMI). Your description of DAQConnect and how it compares to your product is accurate. You are also correct that different tools are appropriate for different applications. DAQConnect is designed to allow those without IT expertise to view their data from anywhere without the security issues of getting into the LAN. Data can come right out of the device so a communications server is not required.

As you say, different things apply to different applications and there are cases where Internet based control is acceptable, namely in cases where changing a value won't hurt anyone or damage anything and appropriate constrains are placed on the values.

Personally, I don't think even ssh tunneling or other secure communications channels are secure enough when control could cause injury or property damage. But then, a properly designed system would never allow ANY control to cause injury or property damage. That is what proper safeties are for.

By bob peterson on 28 September, 2009 - 1:53 pm

Most HMI and SCADA packages come with a set of usable symbols.

By Sergey Sorokin on 15 March, 2011 - 2:05 pm

CSWorks has a free HVAC symbol library, it comes as part of the installation package. All symbols are standard Silverlight controls, 100% scalable, some provide animation capabilities.

Here is the online interactive demo - a simple BAS (building automation system) screen:

More information here: